There was a movie in the 80s' I cannot remember the title. It was about an alien ship that lands in a city(New York, Los Angeles??) It is in female form ( my memory has her looking a bit like a Til Tuesday's AIMEE MANN or Blade Runner's Darryl Hannah type character) She finds a guy on the street who is attracted to her, her begins to kiss her and more, she goes along with it not knowing what this action is but as it progresses into sex, he is taken into her body via vagina. She hates herself for it, but it is a hunger. She continues to explore the human experience but each time she has sex, men are engulfed. She finds one man who is kind to her and respectful. She develops genuine feelings that turn to love. As the evolve, sex becomes a natural inclination and she tries to resist and leave the planet....
I can't remember the name, but I do remember her explaining to this man, sadly, that she loved him, that she did not want to have sex with him because "this p#$$y has teeth..." and to run away from her quickly....
There have been other movie's with similar topics like an episode of the 1990's Outer Limits "Caught in the Act" with Alyssa Milano and AMERICAN GODS and in movie's:Jess Weixler in "Teeth" and Scarlett Johansson in "Under The Skin"